CN100446445C - Protection device and method for optical communication - Google Patents

Abstract

Protection techniques in optical communication networks are very important. An alternative to line protection schemes currently applied in most optical communication networks is to use path protection techniques, where the required working and protection paths are assigned during network setup. During normal operation, in the switching fabric of the network element, only the working path is configured, and the protection path is not configured. If the network unit detects a fault flag in the working path, it searches the protection entry in the routing table of the network unit, determines the required protection switching data, and switches the data service to the pre-assigned protection path. Protection switching data is inserted into the path overhead of the data traffic so that it can communicate with all network elements that need to configure their switching fabric to establish communication protection paths. The protection technique allows similar switching speeds to circuit-switched protection, such as BLSR designs, while increasing the effectiveness of the protection bandwidth.

Description

Protection device and method for optical communication

field of invention

The present invention relates generally to optical communications, and more particularly to apparatus and methods for protection of optical communications.

Background of the invention

Optical communication systems have become vital devices in contemporary society. As this importance grows, maintaining high reliability and signal quality of optical communications infrastructure becomes even more imperative. A number of techniques have been implemented to establish these high standards. A very successful and widely used method of maintaining the integrity of communication networks, even during problems, is the use of line protection.

In an optical communication network, the basic principle of line protection is to generate a working channel and a protection channel for each communication link. In essence, the working channel and the protection channel are the same in bandwidth and function. In normal operation, with no default indicated for either channel, the communication path through the working channel is selected. In the event of a problem with the working channel, the use of line protection allows communications over the working channel to be diverted to the protection channel, minimizing disruption to the actual transmission of information. There are many different configurations of line protection systems which generally create a compromise between the number of optical cables used (hereinafter referred to as Optical Carrier (OC) links) and the level of protection required.

One of the simplest types of line protection is the 1:1 linear protection scheme, as shown in Figure 1A, where each working channel between two network elements (NEs) in the figure has a corresponding protection channel parallel to it. As shown in Figure 1A, these working and protection channels can be in a single OC link, although they are preferably on separate links. Separation of the working and protection channels in the two OC links allows alternative routing for communications in the event that the OC link containing the working channel is disabled. A disadvantage of having separate working and protection channel links is that the high cost of additional OC links can be added to the optical communication network.

In some configurations of line protection, many working channels between NEs share one protection channel, an example of which is shown in Figure 1B. These configurations are called 1:n protection schemes, where n corresponds to the number of working channels that depend on a single protection channel. In the example configuration of FIG. 1B , n is equal to three. The advantage of these 1:n protection system structures is that it can compress the number of OC links required to realize it. Its main disadvantage is that the level of protection to be established is reduced. For example, in the case of this protection system structure, the faults of two or more working channels corresponding to a common protection channel cannot be reversely protected, so if there is no other protection scheme to replace it on the spot, it will lead to unfavorable protection. to the corrected fault.

Another protection technique commonly used in optical communication networks is the Bidirectional Line Switched Ring (BLSR). In a network connected with a BLSR protection scheme, NEs typically including add/drop multiplexers are connected in a serial configuration connected in a circle, as shown in FIG. 2A . Essentially, when configured as a BLSR, communication from any NE in the ring to any other NE in the ring can proceed directly in the clockwise or counterclockwise direction. This allows for completely independent communication routes in case the OC link and/or NE is disabled. Even in BLSR designs, each working channel in each direction is typically protected with a protection channel, allowing multiple transmission options for communications sent over the working channel if the working channel is disabled.

There are two types of general BLSR designs, including two optical cables called 2F BLSR and including four optical cables called 4F BLSR. In 2F BLSR, there is a single OC link between each pair of NEs in each direction through the ring, and the bandwidth of each OC link is usually equally divided between the working channel and the protection channel. In 4F BLSR, there are two OC links between each pair of NEs in each direction of the ring, one OC link corresponds to the working channel in a specific direction, and the other OC link corresponds to the protection channel.

Due to the different protection levels and projected technical requirements between networks, the design of BLSR must be flexible and take into account various modifications. The design of the different BLSRs allows for a modified balance between the number of OC links used and the level of protection provided. For example, there are instances where the BLSR network takes into account data traffic that exceeds the bandwidth of the working channel (hereinafter referred to as hypertraffic), the data traffic being sent over the protection channel instead of the working channel requiring a larger bandwidth. Moreover, some BLSR networks allow for communication between specific NEs that are not protected, the unprotected data traffic being carried in the working and/or protection channels, but with a lower priority level such that the bandwidth used requires For other purposes or when a specific channel used for unprotected data traffic fails, the transfer of unprotected data traffic can be stopped without serious problems. Moreover, similar to linear line protection, some or all of the connections between NEs of the BLSR can be implemented with a 1:n protection system structure in order to compress the number of required protection OC links.

Although these modifications allow for an adjustable configuration of the BLSR system architecture, it can be seen that these modifications also increase the overall complexity of the optical communication network and thus increase the difficulty of network management. Said complexity is especially prevalent when considering combinations of several of the above modifications in a single BLSR. Even when modifications to the standard design are not required, there are still difficulties with BLSR system architecture, one of which is now illustrated with reference to Figures 2A and 2B.

FIG. 2A illustrates a state where data traffic (Data 1) is transmitted within the BLSR from the first NE 50 to the fourth NE 56 through the second and third NEs 52, 54. FIG. 2B illustrates the state of a typical BLSR appearing in FIG. 2A, in which a fault occurs in the OC link connecting the second and third NEs 52, 54 (both working and protection channels). 2B, in the event of a failure between the second and third NEs 52, 54, the data traffic (data 1) sent from the first NE 50 to the fourth NE 56 will be rerouted around the failure. In the general BLSR system structure currently used, the rerouting is by transmitting the data service (data 1) from the first NE 50 to the second NE 52, and then from the second NE 52, through the first, fifth, The sixth and fourth NEs 50, 58, 60, 56, communicate to the third NE 54, and finally from the third NE 54 to the fourth NE 56 to complete. Although this rerouting allows communication between the first and fourth NEs 50, 56 to be maintained, the result of line protection switching makes communications between the first and second NEs 50, 52 and the third and fourth NEs 54, 56 The application efficiency of the OC link is greatly reduced. In both cases, the data traffic (Data 1 ) is returned to its own path twice, thereby reducing the available bandwidth in the effective OC link and additionally increasing the transmission time of the data traffic (Data 1 ). This problem arises from the following reasons: In the usual BLSR design, when an OC link fails, all data traffic passing through the OC link is transmitted along the protection path corresponding to the failed OC link, regardless of the specific The actual path through which data services pass in the network.

There is a technique, commonly referred to as transoceanic swapping, that is often used to eliminate the aforementioned inefficiencies without changing the structure of the BLSR system. When rerouting data traffic after a working channel fails, transoceanic switching takes into account the NEs at the start and end points of each data traffic path under consideration. This consideration essentially transforms the line protection switching scheme of BLSR into a combination of line protection and path protection system structure, improving the efficiency associated with line protection while maintaining the standard BLSR framework. Like other possible modifications of the BLSR design, the problem with transoceanic switching is the complexity of its implementation and the difficulty of managing the entire network.

One technique attempted to address the problems in the design of BLSRs and their many modifications, which is intended to be transferred to mesh protection designs, is shown in Figure 3. In a full mesh design, every NE in the network is connected to every other NE, while in a partial mesh design, fewer OC links are used. The concept of mesh design is to establish a working path for all data traffic in the network when any single failure occurs somewhere and a path protection strategy is adopted. In well-known network designs, when a fault occurs in a working path established between two NEs, the network administrator determines a new working path for the data traffic according to the available bandwidth of the remaining OC links in the network. Well-known mesh technologies have the advantage of minimizing the requirement for dedicated protection path bandwidth, since the optical bandwidth for protection is assigned to the protection path only in the event of a failure, thus reducing the cost of additional optical cables.

A major problem with these well-known network designs is that after a failure occurs, it takes a long time to locate and establish a new working path. The time it takes to re-establish communication after a failure is critical, since the period during the exchange should be small enough that it is negligible for a device or person using the data service. In fact, the speed of protection switching is one of the main advantages of the above-mentioned BLSR design, so removing its complexity and democratizing BLSR design requires adding flexibility.

Therefore, a new protection switching technology is required in the optical communication network. This new protection switching technology has the flexibility to follow specific user requirements and has a switching speed comparable to standard BLSR designs.

Description of the invention

The present invention is directed to protection techniques in optical communication networks. The present invention utilizes a path protection technique that assigns required working paths and protection paths during network establishment, instead of using a line protection scheme for the latest optical communication networks. During normal operation, only working paths are configured in the network element switch fabric along with unconfigured protection paths. Protection paths are assigned by adding protection entries to routing tables in the network elements of the working path. If a fault flag is detected in the working path, the network unit that detects the fault looks up the protection entry in its routing table, determines the modification required for protection switching, and switches the data traffic to the pre-assigned protection path; in its switching structure Implement the required modification in the data traffic; and enter the switching instructions in the path overhead of the data traffic, so that these instructions can be transmitted to all required network elements. This process of pre-assigning protection paths allows for switching speeds similar to circuit-switched protection (eg, BLSR designs), while increasing the effectiveness of the protection bandwidth.

According to a first main aspect, the invention is a network element intended to be coupled in a working path of an optical network. The network element includes a plurality of ports, a switch fabric, a routing table and a control device. The plurality of ports includes first and second ports configured to couple with optical carrier (OC) links in the working path. A switch fabric is connected to the plurality of ports and is configured to couple the first and second ports such that data traffic received by one of the first and second ports is output at the other port. The routing table may be configured to have protection entries entered therein for assigning protection paths having a plurality of network elements with protection entries including protection switching data. The control device is connected to the switch fabric and functions to monitor faults in the working path. If a fault is detected in the working path, the control means further acts to look up a protection entry in the routing table in order to obtain protection switching data and insert the protection switching data into the data traffic output from at least one of the first and second ports in order to configure the protection path. The protection exchange data in the data traffic is adapted to provide instructions for configuring each network element of a protection path requesting reconfiguration in order to establish said protection path.

In some embodiments of the present invention, the routing table may be configured to have a plurality of protection entries inserted therein, each of which is used to assign a corresponding protection path. If a fault is detected in the working path, the control device searches for the protection entry corresponding to the fault among the multiple protection entries in the routing table, and inserts the protection switching data of the found protection entry into the data traffic, and outputs The data service is used to configure a corresponding protection path corresponding to the found protection entry.

According to a second main aspect, the invention is a network element ready to be assigned in a protection path of an optical network. The network unit includes: a plurality of ports; a switch fabric connected to each of the ports; and a control device connected to the switch fabric. The control means function to monitor the data traffic received at one of the ports for changes in the protection switching data. If the protection switching data has changed, the control means is operative to process said protection switching data in order to determine whether any switching instructions in the protection switching data relate to a network element, and if at least one of said switching instructions relates to a network element , then, reconfigure the switching fabric according to the switching instruction related to the network element, so as to configure the network element in the optical network protection path. The protection switching data is generated by a network element in a working path associated with a protection path and is adapted to be transmitted to a network element of the protection path, wherein at least one of the network elements of the protection path is not the working path The path terminal unit for the path.

According to a third main aspect, the invention is a method for establishing an optical communication network of network elements and Optical Carrier (OC) links. The method includes configuring a working path for data traffic between a first path termination network element and a second path termination network element through the first group of OC links and each network element. The method also includes assigning at least one data traffic protection path between the first network element and the second network element through the second set of OC links and each network element. The assignment of at least one protection path includes: inserting a protection entry into a routing table of a network element, and the network element can detect a failure of a working path; the protection entry includes protection switching data, and the protection switching data is determined to be in the first network element The modification to the switching structure needed to configure the protection path between the second network unit includes the modification of the switching structure of the network units of the two groups of OC links and the network units.

According to a fourth main aspect, the invention is a method for configuring a pre-assigned protection path with a plurality of network elements in an optical network during a failure in a pre-configured working path. The method includes monitoring a fault flag in a preconfigured working path. Moreover, if a fault flag is detected in the working path, the method includes: determining protection switching data corresponding to the fault; transmitting the protection switching data in the data traffic to a network element of the protection path, wherein the protection at least one of said network elements of a path is not a trail termination element of said working path; and processing protection switching data for each network element requiring reconfiguration such that its corresponding switch fabric is reconfigured to configure said Protect the path. .

According to a fifth main aspect, the invention is an optical communication network of network elements coupled together with Optical Carrier (OC) links. An optical communication network includes a working path and at least one protection path. The working path includes a first set of OC links and network elements configured to carry data traffic between first and second path terminating network elements. The protection path includes a second set of OC links and network elements assigned to transfer data traffic between the first and second path terminating network elements when a failure is detected on the working path. In this respect, the routing table in the network elements of the working path includes protection entries governing the switching instructions that must be added to the network elements of the protection path in order to configure the protection path.

In each of the above main aspects, the data traffic preferably comprises a plurality of data units, each data unit comprising path overhead additionally comprising at least one guard byte. The at least one protection byte has protection switching data inserted therein in case of failure of the working path. In an exemplary embodiment of the present invention, each data unit is a synchronous transport signal level 1 (STS-1), and the at least one guard byte includes Z3 and At least one of the Z4 bytes.

According to another aspect, the invention is a data frame including a transport overhead and a Synchronous Payload Envelope (SPE). The SPE includes path overhead and payload. The protection switching data is inserted into the path overhead for delivery to the network elements of the protection path and switching instructions are provided to the network elements of the protection path requiring configuration, wherein at least one of the network elements of the protection path is not a path of the corresponding working path end unit. The protection switching data is preferably inserted in at least one of Z3 and Z4 bytes in the path overhead, and the data frame is preferably one of a Synchronous Optical Network (SONET) frame and a Synchronous Digital Hierarchy (SDH) frame.

Other aspects and features of the present invention will be apparent to those of ordinary skill in the art after reading the following description of specific embodiments of the present invention in conjunction with the accompanying drawings.

Brief introduction to the drawings

Preferred embodiments of the present invention will be described below with reference to the accompanying drawings, in which:

Figures 1A and 1B illustrate simple well-known linear line protection optical communication networks;

Figure 2A illustrates the well-known Bidirectional Line Switched Ring (BLSR), describing the specific data traffic paths during normal operation;

Figure 2B illustrates the well-known Bidirectional Line Switched Ring (BLSR), describing the specific data traffic paths during normal operation;

Figure 3 illustrates a well known mesh protected optical communication network;

Figure 4 illustrates a first optical communication network example;

Fig. 5 illustrates the frame structure of STS-N with reference to the SONET standard;

FIG. 6 illustrates an example of the first optical communication network of FIG. 4 with specific working and protection data traffic paths described according to an embodiment of the present invention;

Figure 7A is a flowchart illustrating the steps performed during network establishment in accordance with the preferred embodiment of the present invention;

Figure 7B is a flowchart illustrating the steps performed by the control device in the network element during switching to the protection path according to the preferred embodiment of the present invention;

Figure 8A illustrates a second example of an optical communication network according to an embodiment of the present invention;

Figure 8B illustrates the allocation of OC link assignment bandwidth in the second optical communication network example of Figure 8A;

Figure 9 illustrates a third example of an optical communication network describing specific working and protection data traffic paths according to an embodiment of the present invention;

FIG. 10A illustrates a fourth example of an optical communications network during normal operation, according to an embodiment of the present invention; and

Figures 10B, 10C and 10D illustrate the fourth optical communications network example of Figure 10A during operation, showing various failures.

Detailed description of the preferred embodiment

The present invention is directed to methods and arrangements for improving protection switching in communication networks. The present invention is essentially an improved technique for protecting data traffic over Optical Carrier (OC) links. Unlike the well-known BLSR and linear line protection system architectures, the improved technique described below is directed to path protection system architectures in which working and protection paths are initially assigned, but typically only at the NE Configure the working path in the switch fabric. In the event of failure of the working path, the protection path is configured to carry and thus maintain data traffic flow.

As will be explained below, in some embodiments, the selected protection path to be configured is determined according to the type and location of the fault during the fault. In other embodiments, only one protection path is configured for use during a failure.

As will be explained below, the present invention is preferably designed to operate in the Synchronous Optical Network (SONET) standard, although other standards, such as the Synchronous Digital Hierarchy (SDH) standard, may be seen to be used. Before describing the specific improvements required to implement the present invention, the components and limitations of a generic network conforming to the SONET standard are described to give the context in which the preferred embodiment of the present invention may be implemented.

An example SONET network is depicted in FIG. 4 . As shown, the SONET network example includes: a plurality of network elements (NEs) 100, 102, 104, each NE being a part of the network; line and/or path termination equipment, for example, add/drop multiple Add-drop multiplexer, regenerator or digital cross-connect. In Fig. 4, the NEs 100, 102, 104 in the SONET network example are interconnected by multiple OC links 106, 108, 110, and the NEs 100, 102, 104 are designed to be connected by multiple OC links 106, 108 , 110 send and receive data optically. As is the case in any other SONET infrastructure, most of the transport capacity available on each OC link in the SONET network in Figure 4 is used to carry revenue-generating data traffic (payload), while some capacity (overhead ) is used to manage and control the delivery of the payload. As will be explained below, in the embodiment of the present invention, the payload in each OC link can be subdivided into (as shown in FIG. 4 ) working channel part 112, unprotected channel part 113, protection channel part 114 and Part 115 is not assigned.

According to the SONET standard, each OC link 106, 108, 110 in the SONET network in Fig. 4 can be designed to carry one or more SONET base signals. In SONET, the basic SONET signal is called Synchronous Transport Signal Level 1 (STS-1) and is defined to operate at 51.84 megabits per second (Mbps). In traditional SONET systems, it is common practice to design OC links that can carry multiple STS-1 signals. In general, STS-1 signals are multiplexed together and to form higher order signals that operate at integer multiples of the base STS-1 rate. For example, three multiplexed STS-1 signals may be multiplexed to form an STS-3 signal operating at three times the base rate of 51.84 Mbps or at a rate of 155.520 Mbps. Likewise, 48 multiplexed STS-1 signals can form an STS-48 signal operating at 48 times the base rate of 51.84 Mbps or 2.488 gigabits per second (Gbps). In more complex configurations, OC links can be designed to carry up to 192 multiplexed STS-1 signals and provide a transmission capability close to 10Gbps. An OC link capable of carrying 192 multiplexed STS-1 signals is generally called an OC-192 link.

In the SONET network of Figure 4, OC links 106, 108, 110 can be designed to meet the needs of various capacities, but, for the sake of example, the OC links 106, 108, 110 will be assumed to carry 192 STS- 1-signal OC-192 link. It should be understood that links 106, 108, 110 and all other OC links illustrated in the other figures described below could be selectively designed to have lower transmission capacity and carry fewer STS-1 signals, if desired, even Can be designed to have a higher transmission capacity, and future transmission technologies may allow this increase.

For the transmission of STS-N signals, such as STS-192 signals (N=192), SONET defines a standard STS-N frame structure, which includes the envelope capacity and in each field of overhead information. Figure 5 shows an example of a standard STS-N frame defined in SONET. The STS-N frame shown in Fig. 5 is composed of N STS-1 frames 122, 124, 126 (only three are shown), and in SONET, these frames are numbered 1 to N respectively. Normally, the number N of the STS-1 frame 120, 122, 124 included in the STS-N frame corresponds to the number N of the STS-1 signal carried in the STS-N signal. For example, for an OC-192 link, an STS-N frame consists of 192 STS-1 frames, and each frame corresponds to one of the multiplexed 192 STS-1 signals.

Among the STS-N frames, the STS-1 frames 120, 122, 124 are formed according to the standard frame format defined in SONET. Considering a specific STS-1 frame 120, the format of said STS-1 frame defined in SONET is a definite sequence of 810 bytes or 6480 bits arranged in a structure of 90 columns x 9 rows, wherein each column includes 9 words section and each row consists of 90 bytes. According to SONET, an STS-1 frame 120 has a frame length of 125 microseconds. It is possible to transmit 8000 STS-1 frames per second with a frame length of 125 microseconds, for example, 120 STS-1 frames. Considering that each STS-1 frame contains 6480 bits, the rate at which STS-1 signals can be transmitted is given by:

The rate of STS-1=6480 bits/frame*8000 frames/second;

= 51.84Mbps

As noted above, it is the basic rate for SONET.

Considering the STS-1 frame 120 in more detail, the first three columns (column 1 to column 3) of the frame 120 are used for transmission overhead 126, and the remaining columns (column 4 to column 90) determine the Synchronous Payload Envelope (SPE) 128. SPE 128 consists of 783 bytes and can be described in a structure of 87 columns x 9 rows. SPE 128 is mainly used to carry payload data, however, the first column consisting of 9 bytes is assigned to path layer overhead 130 (hereinafter referred to as path overhead). The overhead bytes included in path overhead 130 are labeled J1, J2, B3, C2, G1, F2, H4, Z3, Z4 and Z5, respectively. In addition to the Z3 and Z4 bytes, the trail overhead bytes are used for various trail control functions, including signal characteristic monitoring and maintenance between trail termination devices. The Z3 and Z4 bytes are currently not assigned any specific control function, but were set for user purposes in the previous state of the art. The same is true for all other Z3 and Z4 bytes present in each STS-1 frame 120, 122, 124 of the STS-N frame.

The transmission overhead 126 is located in the first three columns of the STS-1 frame, and these columns contain 27 bytes in total. Among these bytes, 9 bytes are assigned to the partial layer overhead 132 (hereinafter referred to as partial overhead), and 18 bytes are reserved for the line layer overhead 134 (hereinafter referred to as line overhead). The partial overhead 132 is located in row 1 to row 3 of the transmission overhead 126 and is generally used to support partial control functions, the latter including signal characteristic monitoring, management, maintenance and connection between partial terminal equipment. Line overhead 134 is located in row 4 to row 9 of transport overhead 126 and is generally used to support control functions of the line, eg, signal multiplexing, protection switching and maintenance between line terminating equipment.

In the present invention, improvements are made in how protection switching occurs in optical networks. These improvements require modifications in the SONET standard mentioned above. In the current line protection system architecture, the line overhead 134 has two bytes into which the protection switching data for a particular link is inserted during a fault, these bytes are the K1 and K2 bytes illustrated in Figure 5 . In case of a failure in a particular OC link, the protection switching data provides the required alternative path information. In this case, if there is a failure in a particular OC link, all data traffic passing through said OC link will be redirected by the protection path specified by the K1 and K2 bytes, so that the data traffic still reaches the failed OC link On the NE at the other end of the road. As mentioned above, the protection path may be a protection OC link parallel to the working OC link, or the protection path may consist of a number of OC links directing data traffic in the opposite direction along the BLSR until it reaches the faulty OC link On the NE at the other end of the road.

In the present invention, protection switching data is not inserted into the line overhead 134, however, it is preferably inserted into the path overhead 130 during a fault. More specifically, protection switching data is preferably inserted in Z3 and Z4 bytes which are not currently used by the SONET standard. Of course, other bytes in the path overhead could be used for a similar purpose if redefined or included in a different standard.

As will be explained below, the details of protecting the exchanged data vary from embodiment to embodiment, but the essence of the preferred embodiment of the invention is to protect the assignment of paths in the optical network during network setup and in the path overhead in case of failure. Insertion of protection switching data indicating the need for reconfiguration in order to direct said data traffic along the assigned protection path. The protection switching data can be regarded as a trigger parameter of the network element receiving it, because, when a fault is detected in the working path, the processing of the protection switching data by other available network elements in the optical network, A reconfiguration of their switch fabric is triggered in order to establish protection paths.

Referring now to FIG. 6, a simple embodiment of the present invention will be described. In Fig. 6, an example of the optical communication network of Fig. 4 is shown, and the working and protection paths of the data service (Data 1) are also described. As shown, a first NE 100 receives data traffic (Data 1) and forwards it to a second NE 102 over the OC link 106. The NEs 100, 102 in this case are path terminating equipment with OC links 106 constituting a working path for a particular data traffic. As shown in FIG. 6, an alternative path for transmitting data traffic (Data 1) is assigned from NE 100 to NE 102 via OC link 108, NE 104, and OC link 110.

As shown in FIG. 6, in the described example, NE 100 includes: ports P1, P2, P3 coupled with respective OC links; switch fabric 136 coupled between each port P1, P2, P3; a control means 137 coupled to the structure 136; and a routing table 138 coupled to the control means 137. The operation of each of these components is described in detail below. It should be seen that the other NEs 102, 104 have similar structures, and in fact, other NEs in the other figures described below preferably have similar structures in accordance with the present invention.

The following is a process for establishing a working path and a protection path according to the preferred embodiment of the present invention, described with reference to FIG. 7A. The process can be implemented manually by a network administrator, or some of the steps can be automatically implemented by applying a set algorithm that will be described below.

First, as described in step 140, the required level of protection for each data traffic path must be determined by the network administrator, and there may be several different levels of protection. Some of these protection levels include (and are not limited to) 1:1 protection, 1+1 protection, unprotected data traffic, and 1:n protection. Each specific protection level is illustrated below by way of example. In the situation depicted in Fig. 6, for the data traffic (Data 1), the 1:1 protection scheme is selected.

In the network establishment process as described in FIG. 7A, the next step is to determine the best OC link and NEs for each working path and protection path at step 141, which must be configured according to the determined protection level. This can be done manually by the network administrator, as long as the network administrator has knowledge of the overall network layout, or can be done automatically using routing methods, eg, Dijkstra's algorithm. In the case of using the Dijkstra algorithm to determine the working path and protection path of the data service, theoretically the best shortest path obtained is selected as the working path of the data service, and the next best shortest path is selected as the protection path. It should be understood that other considerations, such as load and cost with respect to a particular OC link, may also have an impact on path selection.

Once any desired working paths are selected, the switching fabric of the NEs associated with the working paths must be properly configured, as described in step 142 . The configuration of the switch fabric in each NE specifies where the particular data traffic is to be sent. More specifically, the data traffic arriving at the first port of the NE connected to the second port through the switch fabric will be output through the OC link corresponding to the second port. The combined effect of the various switch fabric configurations is to determine which OC link and NE to use if data traffic is received through a particular port of a trail terminating NE during the active state.

In addition, once any desired protection paths have been selected, routing table entries for faults detected in the working paths must be entered, as described in step 143 of FIG. 7A. That is, in order to assign a protection path in the optical communication network, a protection entry is added to the routing table in each NE of the working path. Each entry includes protection switching data that must be inserted in the path overhead protection bytes in the event of a specific failure. The protection switching data indicates the modifications that need to be made in the switching fabric of the NEs included in the protection path in order to re-route data traffic.

In the present invention, the control device in the NE that detects failures in the working path determines which protection entry in the routing table must be added to the switching structure through a search process. The fault-detecting control means in the NE then inserts the protection switching data into the path overhead of the data traffic, more precisely, for the preferred embodiment, into Z3 and/or Z4 bytes which are not currently used. Furthermore, the control means of the NE which detected the failure should reconfigure its switching structure according to the protection switching data, if appropriate. For other NEs of the optical network, the corresponding control device reads Z3 and/or Z4 bytes to determine whether protection switching data is inserted. If there is a protection data inserted (compared with default data), the control means process said data to determine whether their particular switch fabric needs to be reconfigured, and if so, how their switch fabric should be reconfigured in order to configure the protection paths.

In the optical communication network example of Fig. 6, NE 100 has the switching fabric 136 of such configuration, make any data traffic received at port P1 during normal operation be sent out via port P2 on the OC link, and NE 102 has such The switch fabric is configured such that any data traffic received on port P6 of OC link 106 is output on port P7. In addition, NE 100 and NE 102 (the NEs of the working path) have their routing tables with protection entries indicating that if a failure occurs in the working path (OC link 106), then the protection entry The indicated protection switching data will be inserted into the Z3 and/or Z4 bytes of the path overhead of said data traffic. In the case of the example, the protection switching data includes: reconfiguring the switching structure of the NE 100, so that the protection switching instructions of the port P1 and the port P3 are coupled together; the configuration of the switching structure of the NE 104, so that the port P4 and the port P5 are coupled together and a switching instruction for reconfiguring the switching structure of the NE 102 so that the port P8 and the port P7 are coupled together. During normal operation, using the switching fabric of these configurations, the data service (data 1) received at port P1 can be output to port P7 through port P2, OC link 106, port P6 and NE 102.

The operation of the control means in the network element during switching to the protection path will now be described with reference to FIG. 7B. Initially, as described in step 144, the control monitors any OC links to which the NEs are coupled using well-known techniques for any indication of failure. In case a fault flag of an OC link in the pre-configured working path is detected, as described in step 145, the control device searches its routing table for a protection entry corresponding to the detected specific fault. A protection entry designates protection switching data, the latter containing several switching instructions that must be implemented in the optical network in order to configure the switching fabric such that data traffic passes through said protection paths. Here, the NE inserts (in step 146) the protection switching data in the protection bytes in the path overhead of the STS-1 signal including the data traffic. In the protection switching data there may be switching instructions for the specific NE that detected the failure; said instructions are determined in step 147 .

If at step 147 there is a switching instruction corresponding to a particular NE in the protection switching data inserted into the protection byte, then at step 148 a reconfiguration of the switching fabric according to the switching instruction occurs. The content of the switch command corresponding to a particular NE indicates that the particular NE is to be in the protection path. Once a reconfiguration of the switch fabric occurs in step 148, or no reconfiguration is required in step 147 (indicating that the particular NE will not be in the protection path), then, in step 149, the NE will put Data traffic with protection switched data is output to the ports specified by the configuration of the switch fabric. At this time, the calculation performed by the control device in the NE returns to step 144 .

In step 144, if no failure is detected in the OC link to which any NE is coupled, then, in step 150, the control means will monitor the incoming data traffic for any change in the protection byte. As described in step 146, when the working path does not fail, the protection byte will be in a default state, and once the working path fails, protection switching data is inserted into the protection byte. If the protection byte of the incoming data traffic has not changed, then the process of FIG. 7B returns to step 144. In FIG. 7B, although steps 144 and 150 are illustrated as independent steps, it should be understood that these monitoring operations are preferably performed continuously by the control means in each NE of the optical network.

If a change in the protection byte is detected at step 150, then, at step 151, the control means continue to process the protection switched data inserted in the protection byte. At this time, the process performed by the control means goes to step 147 as described above, and at step 147, it is determined whether there is a switching instruction in the protection switching data corresponding to the specific NE. If there is a switching instruction associated with a specific NE, the control means reconfigures the switching fabric according to the switching instruction. Regardless of the presence or absence of a reconfiguration of the switch fabric, the control device outputs the data traffic containing the protection switch data in the protection bytes to the ports specified by the configuration of the switch fabric.

Now, returning to the example of FIG. 6, if a failure occurs in OC link 106, then NE 100 and/or NE 102 will detect the failure. For simplicity, only the case where the NE 100 detects a fault is described. As a result of detecting a fault, the control means 137 in the NE 100 will perform an operation of looking up the routing table to determine the protection entry corresponding to such a fault (step 145). In this case, the protection entry will have protection switching data similar to that described above; the protection switching data includes switching instructions for each of NE 100, NE 104 and NE 102. Next, the control device 137 will insert the protection switching data into the protection byte in the path overhead of the data service (data 1) (step 146), and determine whether any switching instructions are relevant to the switching fabric 136 in the NE 100 (step 147 ). In the case of FIG. 6, there is indeed a switch instruction corresponding to NE 100, which is an instruction to reconfigure switch fabric 136 such that port P1 and port P3 are coupled together. The control device therefore proceeds with the commanded reconfiguration in the switch fabric 136 (step 148). After performing said reconfiguration in NE 100, the data traffic (data 1) received at port P1 is then output via port P3, which transfers the data traffic of the protection switching data in the protection bytes with path overhead via the OC link 108 leads to NE 104 (step 149).

At this moment, NE 104 will receive data traffic (data 1) on port P4, and detect the non-default protection byte (step 150) in data traffic (data 1). This results in the processing of the protection switching data in the protection bytes (step 151) and determining that there is a switching instruction for the switching fabric of the NE 104 (step 147) that configures the switching fabric such that port P4 and port P5 are coupled instructions together. Then, the control device of NE 104 will configure its switch fabric according to the instruction (step 148) and output the data service (data 1) configured by the switch fabric through port P5, as a result, receive data service at NE 102 via OC link 110 (Data 1) (step 149).

In addition, a process similar to that described above for NE 104 will be performed in NE 102 to reconfigure its switch fabric (steps 150, 151, 147, 148 and 149 in FIG. 7B). Alternatively, since the control device in the NE 102 can directly detect a failure in the OC link 106, the control device in the NE 102 can continue to perform similar steps as described above for the NE 100 (steps 144, 145, 146 of FIG. 7B , 147, 148 and 149). Finally, when OC link 106 fails, data traffic (data 1) received at port P1 will go through port P3, OC link 108, port P4, NE 104, port P5, OC link 110, port P8 and NE 102 is output to port P7, which is the protection path selected in the previous step.

It should be seen that in the preferred embodiment of the present invention, the working path and the protection path are bidirectional paths. The above examples are concrete and easy to illustrate simple one-way systems. Therefore, during normal operation, with the same working path configuration and protection path assignments, any data traffic received at port P7 in NE 102 will be delivered via port P6, OC link 106, port P2, and NE 100 to Port P1. Also, during the failure of OC link 106, the reconfiguration of the switch fabric obtained in NE 100, 102, 104 will cause any data traffic received at port P7 to pass through port P6, OC link 110, port P5, NE 104, port P4, OC link 108, port P3 and NE 100 forward to port P1.

It should be noted that other port configuration and protection entries may be included in the respective switching fabrics and routing tables of the NEs 100, 102, 104 for other data traffic paths not discussed. Essentially, the entire optical communication network can be seen as many communication paths multiplexing the various NE and OC links, and each path is defined with its own set of input and output ports. In the example of Fig. 6, only one communication path is defined. In this case, during network establishment, the selection of the working path and the protection path should ensure that the protection is maintained, and both the working path and the protection path have reserved bandwidth. It should be noted that, as will be explained below, in some embodiments the reserved bandwidth of the protection path is shared with the protection paths of other communication paths, while in other embodiments it is not shared.

In general, according to the present invention, the paths involved in the optical communication network may be any of a number of different protection schemes and levels of protection discussed below. In fact, with the aid of the invention, each path can have a different scope of protection dedicated to its type, the priority of the data traffic for which said path will be used, the availability of optical cables and/or customer the desired configuration.

Before discussing more complex optical communication networks, referring now to Figures 8 to 10, some different methods of protection are illustrated. It should be noted that the protection schemes and levels described below are not meant to limit the scope of the present invention, in fact, the flexibility of the present invention allows for various different protection schemes not discussed here.

Some well-known protection schemes that can be applied in optical communication networks according to the present invention are 1:1 protection scheme, 1:n protection scheme and unprotected data traffic as shown in FIG. 6 . In addition, the network elements in the network can be configured as a ring similar to the BLSR design, and the working path and the protection path are configured separately in the ring.

When considering the level of protection, it should be taken into account that the marking of the bandwidth assignment is reserved in the relevant OC link. As previously explained with reference to FIG. 4, the OC link is preferably subdivided into a working channel portion 112, an unprotected channel portion 113, a protected channel portion 114 and an unassigned portion 115. In the preferred embodiment of the present invention, the working channel 112 is used as a bandwidth reservation part of one or more working path parts; the unprotected channel part 113 is used as a bandwidth reservation of one or more data traffic paths without protection paths part; the protection channel part 114 is the reserved part of the required bandwidth, which ensures that bandwidth is available if a protection path must be configured; and the unassigned part 115 is the remaining bandwidth that other data traffic can use. These reserved bandwidth portions are preferably maintained in the control software using well known techniques.

According to the present invention, the flexibility of the optical communication network can be extended, so that the efficiency balance between the network and each data traffic path can be maintained under suitable conditions. Figure 8A illustrates an example of an optical communications network comprising five NEs that can carry data traffic along five data traffic paths, in which the present invention can be implemented. In Figure 8A, the first NE 160 is coupled to the second NE 162 via OC link A; the second NE 162 is coupled to the third NE 164 via OC link B; the first NE 160 is coupled to the third NE via OC link C 164; the first NE 160 is coupled with the fourth NE 166 via OC link D; the fourth NE 166 is coupled with the fifth NE 168 via OC link E; and the fifth NE 168 is coupled with the third NE 164 via OC link F coupling. In the network example, data traffic (data 1) is transmitted between the first NE 160 and the third NE 164; data traffic (data 2) is transmitted between the first NE 160 and the second NE 162; data traffic ( Data 3) is transmitted between the second NE 162 and the fourth NE 166; data traffic (data 4) is transmitted between the fourth NE 166 and the third NE 164; and data traffic (data 5) is transmitted between the third NE 162 and Teleport between fifth NE 168.

Figure 8B illustrates reserved bandwidth in the OC link of Figure 8A. In this example, data traffic (Data 1) has a configured working path via OC link C and an assigned protection path via OC links A and B; data traffic (Data 2) has a configuration via OC link A working path and assigned protection path via OC links C and B; data traffic (Data 3) has a configured unprotected path via OC links A and D; data traffic (Data 4) has a configured unprotected path via OC links C and F's configured working paths and assigned protection paths via OC links D and C; while data traffic (Data 5) has configured unprotected paths via OC links B and F.

In the example illustrated in Fig. 8A and Fig. 8B, it can be seen that the protection part in OC link A is reserved for the protection path of data traffic (data 1); the protection part in OC link B is reserved for the protection path of data traffic (data 1). shared between the protection paths of data traffic (data 2) and data traffic (data 2); the protection part in OC link C is shared between the protection paths of data traffic (data 2) and data traffic (data 4); OC The protection part in link D is reserved for the data traffic (data 4) protection path; while OC links E and F do not reserve any protection part. In the case of the shared protection part of OC links B and C, it should be noted that this implementation including the shared protection part only guarantees protection against a single fault in the optical communication network, but not in the following cases: due to network Due to multiple faults in the network, it is necessary to share two data service protection paths of a reserved protection part.

There are a number of techniques for multiple failure scenarios in an optical communication network, similar to the one illustrated in Figure 8A. For example, a priority hierarchy of different protection paths can be established. For example, in the case where the protection paths of data traffic (Data 2) and data traffic (Data 4) both require the protection part in OC link C due to failures in OC links A and F, data traffic (Data 2 ) protection path may take precedence. Priority may be based simply on the order in which faults occur, or on the type or importance of the data being transferred. On the other hand, even if the protection part is being used by the first protection path when it is needed by the second protection path, assuming that the unassigned part has enough bandwidth, it may choose to configure in the unassigned part of the OC link Second protection path. In the implementation example of FIGS. 8A and 8B , OC link A has almost enough bandwidth in the unassigned portion to accommodate additional guard bandwidth beyond that contained in the guard portion.

In addition, an additional solution to the problem of sharing the protection part in the case of multiple faults is to have a larger protection part in the case of a shared protection part. The described solution has the disadvantage of increasing the number of reserved bandwidth resources required, but this may be required when 1:1 or 1+1 protection must be guaranteed. Another solution to the problem in case the first protection path cannot be configured is to assign the second protection path to a specific communication path. The disadvantage of the solution is that it increases the complexity, and in the case of one working path with multiple protection paths, it also increases the required bandwidth resources.

In the examples shown in FIG. 8A and FIG. 8B , data traffic (data 3 ) and data traffic (data 5 ) have only unprotected data paths, possibly due to the low priority of the data traffic. In some embodiments of the invention, although unprotected paths do not reserve protection bandwidth in the OC link, there is still an option to assign protection paths during network setup. In this case, as described above, the assignment of protection paths includes the insertion of protection entries into the routing tables of the affected NEs, but does not include the ability to use bandwidth in the protected part of the reserved OC link. Only any bandwidth in the unassigned portion of the associated OC link can be used in the event of failure of the unprotected path.

In FIG. 8B, although the bandwidth corresponding to the OC link is the same, it should be understood that this is for a simple example. In another embodiment, the OC links in the optical network may have various bandwidths. Moreover, in FIG. 8B, although the bandwidth requirements of each group of data services shown are the same, people should understand that the bandwidth requirements of different data services may be different. The protection portion reserved in a particular OC link preferably has sufficient bandwidth to protect the corresponding working path with the greatest bandwidth requirement.

Figure 9 illustrates an optical communication network that demonstrates the additional flexibility that can be obtained by means of the present invention, which cannot be obtained using conventional protection techniques, the additional flexibility is reconfiguration in the event of a failure in the optical working path The ability to form an optical path that is only part of the data path. More specifically, if the service access point fails, prior protection techniques will not be able to correct said failure, but as described below, it is possible to correct said failure by means of the present invention depending on the situation.

As shown in FIG. 9, four routers 170, 172, 174, 188 and five NEs 176, 178, 180, 182, 184 are interconnected in an optical communication network. 9, NE 176 is connected with NE 178, NE 180 and router 172; NE 178 is also connected with NE 180, NE 182 and router 174; and NE 182 is also connected with NE 184 and router 170. Additionally, routers 170 , 172 , and 188 are individually connected to a local area network (LAN) 186 . In the example illustrated in FIG. 9, the working path is configured between router 188 and router 174 via LAN 186, router 172, and NEs 176, 178. In that case, if a service access point, e.g. NE 176, fails, then the remaining components of the optical network cannot compensate for the failure by themselves.

In an embodiment of the invention, if the network administrator knows that router 188 is capable of transmitting data traffic to and receiving data traffic from router 170 via LAN 186, then the protection path can be assigned to such a router during network setup. kind of failure. In this case, if some form of higher layer protection scheme is appropriate for the data traffic transmitted via router 170 in the event of a failure, then the traffic between router 188 and router 174 to assign total protection paths. At a higher level, this could be achieved by a constant connection between router 170 and router 188 and a working path connection between router 172 and router 188, or alternatively, by another protection linking routers 170, 188 during a failure The form is realized.

As long as there is a technique for routers 170, 188 to connect during a failure, the NE of FIG. 9 can compensate for a failure in NE 176 by establishing a protection path between router 170 and router 174. This can be achieved by inserting protection portals into the NEs 176, 178 which include the switching fabric of the NEs 178, 182 to accommodate reconfiguration in the event of a failure.

In this case, if the NE 178 detects a failure in the NE 176, then the control device in the NE 178 will look up its routing table in order to determine the corresponding protection entry, which includes a switch instruction with the NE 178 The protection exchange data and the exchange order of NE 182. Then, the control device of NE 178 inserts the protection switching data into the protection bytes in the path overhead of the data traffic, reconfigures its switching structure according to the switching instruction, and outputs the data traffic received by the router 174 to the NE 182 (according to its reconfiguration in the switch fabric). Then, the control device in the NE 182 will detect the non-default protection byte in the received data traffic, process the protection switching data in the protection byte, reconfigure its switching structure according to the corresponding switching instruction, and output the data traffic to the router 170. Assuming that the routing between router 172 and router 188 is switched between router 170 and router 188, then router 188 and router 174 may communicate over the overall protection path. In previous network configurations, attempts to configure the optical communication network of FIG. 9 did not consider components other than NEs of the optical communication network.

In an exemplary embodiment of the invention, the type and location of the fault in the working path dictates the protection path to be used. This is achieved by causing different faults in the network to generate different protection entries (that is, protection switching data) in the searched routing table.

10A to 10D illustrate an optical communication network whose data traffic paths utilize the protection scheme according to this exemplary embodiment of the present invention. In this case, the working path occurs between NE 200 and NE 208 via NE 202, 204, 206, and the protection path passes through NE 210, 212, 214, 216, 218, via NE 202, 204, 214, 216, 218 And appear between NE 200 and NE 208 through NE 210, 212, 214, 204, 206.

Figure 10A illustrates an optical communications network under normal operation with no indication of failure-free occurrences in the working path. FIG. 10B illustrates the optical communication network of FIG. 10A when a fault occurs between NE 202 and NE 204. At this time, the protection path used surrounds the fault, and the NE and OC links of the working path should be used as much as possible. Therefore, only the switching fabric in the NE 200, 210, 212, 214, 204 has to be reconfigured (ie the switching instruction 5 in the protection switching data), and the minimum number of reserved protection parts in the OC link must be used. FIG. 10C illustrates the optical communication network of FIG. 10A in the event of a failure between NE 204 and NE 206. Similar to FIG. 10B , the protection path used at this time surrounds the fault, and at the same time, the NE and OC links of the working path are used as much as possible. Therefore, only the switching fabric in the NEs 204, 214, 216, 218, 208 must be reconfigured (i.e. the switching instruction 5 in the protection switching data), and similar to Fig. 10B, the minimum number of reserved protection parts in the OC link must be used . FIG. 10D illustrates the optical communication network of FIG. 10A in the event of a failure in NE 204. At this time, the protection path used completely surrounds the fault, and the NE and OC links of the working path are not used at the same time (that is, the switching instruction 7 in the protection switching data).

In the above example, the network administrator of the optical communication network seeks to use as many working path components as possible during a failure and therefore must use a minimum number of protection sections and reconfigure a minimum number of switch fabrics. The implementation of the preferred embodiment of the invention allows the required flexibility to be used for this purpose.

Although the invention has been described above with respect to the SONET standard, it should be clear that other data services not defined by SONET are also applicable. An important aspect of the present invention is the ability to propagate protection switching instructions via the protection bytes of the path overhead in the data traffic, which provides for fast and reliable switching of the switching fabric under failure conditions.

Those skilled in the art understand that there are more alternative implementation solutions and possible modifications to realize the present invention, and the above implementation solutions are only illustrations of some embodiments of the present invention. Accordingly, the scope of the invention is limited only by the appended claims.

Claims (37)

1. a preparation is coupling in the network element in the operating path of optical-fiber network, and described network element comprises:

A plurality of ports, they comprise first and second ports of light carrier (OC) link couples in preparation and the described operating path;

Switching fabric, it is connected with described a plurality of ports and described first and second ports that are configured to be coupled like this, make the data service that receives in described first and second ports one export on another port;

Routing table, it can be configured to have and be input to being used in this routing table and assign the protection inlet in protection path, and described protection path has a plurality of network element, and described protection inlet comprises the protection swap data; And

Control device, it is connected with described switching fabric, it plays the fault in the described operating path of monitoring, and, if in described operating path, detect fault, then in described routing table, search described protection inlet so that obtain described protection swap data, and described protection swap data is inserted in the described data service of at least one output from described first and second ports;

Wherein, the described protection swap data in the described data service comprises the exchange instruction of each described network element that the request that is used to dispose described protection path reconfigures, so that set up described protection path.

2. network element as claimed in claim 1 is characterized in that: described data service comprises a plurality of data cells, and each data cell comprises path cost, and described path cost comprises at least one guard byte again; And

For described protection swap data is inserted in the described data service, described control device is inserted in described protection swap data at least one guard byte.

3. network element as claimed in claim 2; it is characterized in that: each described data cell comprises Synchronous Transport Signal level 1 (STS-1) and at least one guard byte, and described at least one guard byte is included in the Z3 that defines in the described path cost of each STS-1 and at least one in the Z4 byte.

4. network element as claimed in claim 1, it is characterized in that: it is wherein each from a plurality of protection inlets that are used to assign the corresponding protection path that described routing table can be configured to have input, described protection path has a plurality of network element, described a plurality of protections each self-contained protection swap data that enters the mouth; And

Wherein, if in described operating path, detect fault; so; described control unit is suitable for having on described road the protection inlet of searching in the option table in the described a plurality of protection inlet corresponding to described fault; and the described protection swap data of the described protection inlet that will find inserts in the described data service of at least one output from described first and second ports, so that set up the corresponding protection path corresponding to the described protection inlet that finds.

5. network element as claimed in claim 1 is characterized in that: described protection swap data comprises a plurality of exchange instructions of the switching fabric of described each network element that is used for described protection path.

6. network element as claimed in claim 5 is characterized in that: described a plurality of ports also comprise the 3rd port of preparing to be coupled to the OC link of protecting the path;

Wherein, the exchange instruction in the described protection swap data is determined to reconfigure described switching fabric like this, make the described first and the 3rd port be coupled; And

Wherein, if detect fault in described operating path, then described control device also plays a part to reconfigure described switching fabric according to the exchange instruction of described correspondence.

7. network element as claimed in claim 1 is characterized in that: described data service is by Synchronous Optical Network (SONET) standard definition.

8. network element as claimed in claim 1 is characterized in that: described data service is by synchronous digital hierarchy (SDH) standard definition.

9. a preparation is assigned to the network element in the protection path of optical-fiber network, and described network element comprises:

A plurality of ports;

The switching fabric that is connected with each described port; And

With the control device that described switching fabric is connected, described control device comprises:

Be used for monitoring the unit of variation of the protection swap data of the data service that receives at one of described port; wherein; described protection swap data by with operating path that described protection path is associated in network element produce and be suitable for being sent to the network element in described protection path; at least one is not the Trail termination unit of described operating path in the described network element in described protection path

Whether be used for handling described protection swap data under the situation that described protection swap data has taken place to change has the unit of any exchange instruction relevant with described network element so that determine described protection swap data,

Be used for reconfiguring described switching fabric so that in the described protection path at described optical-fiber network the unit of the described network element of configuration according to the described exchange instruction relevant under described exchange instruction at least one situation relevant with described network element with described network element.

10. network element as claimed in claim 9 is characterized in that: described data service comprises a plurality of data cells, and each data cell comprises path cost, and described path cost comprises at least one guard byte again; And

Wherein, the described protection swap data in the described data service is arranged in described at least one guard byte.

11. network element as claimed in claim 10; it is characterized in that: described each data cell comprises Synchronous Transport Signal level 1 (STS-1), and described at least one guard byte is included in the described Z3 that defines in the described path cost of each STS-1 and at least one in the Z4 byte.

12. network element as claimed in claim 9 is characterized in that: described a plurality of ports comprise first and second ports of preparing to be coupled to light carrier in the operating path (OC) link;

Wherein, described switching fabric be configured to be coupled so described first and second ports, make the data service of a reception in described first and second ports in another port output; And

Wherein, described control device is also monitored the fault in the described operating path; if and in described operating path, detected fault, would then determine in protection swap data corresponding and the described data service described protection swap data insertion at least one port output from described first and second ports with described fault.

13. network element as claimed in claim 12 is characterized in that also comprising the routing table that comprises at least one protection inlet;

Wherein, in order to determine the protection swap data corresponding with described fault, described control device is searched the protection inlet corresponding with the described fault in the described operating path in described routing table, and described protection inlet comprises the protection swap data.

14. network element as claimed in claim 9 is characterized in that: described data service is by Synchronous Optical Network (SONET) standard definition.

15. network element as claimed in claim 9 is characterized in that: described data service is by synchronous digital hierarchy (SDH) standard definition.

16. a method that is used to set up the optical communication network of network element and light carrier (OC) link, described method comprises:

Through first group of OC link and each network element, dispose the operating path of the data service between the terminal network unit, first path and the second Trail termination network element; And

Through second group of OC link and each network element, assign at least one protection path for the data service between described first network element and described second network element, the operation at least one protection path of described appointment comprises:

Protection inlet is inserted in the routing table of the network element that can detect the fault in the described pre-configured operating path; described protection inlet comprises the protection swap data; the protection swap data indicates the described pre-configured required switching fabric modification in protection path of configuration between described terminal network unit, first path and the described second Trail termination network element, comprises each network element of described second group of OC link and the switching fabric of described each network element are revised.

17. method as claimed in claim 16 is characterized in that: the operation of the operating path of described configuration data business is included in a plurality of described network element and disposes switching fabric, so that transmit described data service through described operating path.

18. method as claimed in claim 17 is characterized in that: the operation of the operating path of described configuration data business also comprises the bandwidth that is preserved for through the data service of first group of OC link.

19. method as claimed in claim 16 is characterized in that: the operation at least one protection path of described appointment data service also comprises the bandwidth that is preserved for through the data service of second group of OC link.

20. method as claimed in claim 16 is characterized in that: the operation at least one protection path of described appointment data service comprises through the OC link group of a plurality of correspondences and network element assigns a plurality of protections path that is used for described data service from described first network element to described second network element.

21. one kind is used for having the protection route method of the pre-appointment of a plurality of network element in the optical-fiber network configuration during pre-configured operating path breaks down, described method comprises:

Monitor the fault flag in the described pre-configured operating path; And

If in described operating path, detect fault flag: then

Determine the protection swap data corresponding with described fault, described protection swap data comprises the exchange instruction in the described protection of each network element configurations path in the described protection path that request reconfigures;

Send the described protection swap data in the described data service the described network element of described protection path to, at least one is not the Trail termination unit of described operating path in described each network element in described protection path; And

The described protection swap data of each described network element that the request handled reconfigures, make its corresponding switching fabric be reconfigured so that dispose described protection path.

22. method as claimed in claim 21 is characterized in that: described data service comprises a plurality of data cells, and each data cell comprises path cost, and described path cost also comprises at least one guard byte; And

Wherein, the described protection swap data in the described data service of described transmission comprises and inserts described protection swap data in described at least one guard byte of described path cost and transmit described data service.

23. method as claimed in claim 22 is characterized in that: each described data cell comprises that Synchronous Transport Signal level 1 (STS-1) and described at least one guard byte are included in the Z3 that defines in the described path cost of each STS-1 and at least one in the Z4 byte.

24. method as claimed in claim 21; it is characterized in that: the described operation of determining the protection swap data corresponding with described fault be included in the corresponding routing table of described fault flag in search the protection inlet, described protection enters the mouth and comprises described protection swap data.

25. method as claimed in claim 21 is characterized in that: described protection swap data comprises many exchange instructions about the described network element in the described protection path of needs exchange.

26. the optical communication network with light carrier (OC) link couples network element together, described optical communication network comprises:

The operating path that comprises an OC link group and network element, they are configured to data services between the first and second Trail termination network element; And

Comprise at least one protection path of the 2nd OC link group and network element, if detect fault on described operating path, then they are assigned the next data service that transmits between the described first and second Trail termination network element;

Wherein, for each network element of described operating path, the routing table in the described network element comprises the protection inlet of determining exchange instruction, and described exchange instruction must be added to the described network element in described protection path so that dispose described protection path.

27. network as claimed in claim 26; it is characterized in that: if break down at described operating path; the described network element detection failure of then described first group at least one; determine the protection swap data by the protection inlet of in its routing table, searching described correspondence, and described definite protection swap data that will comprise its exchange instruction inserts in the described data service.

28. network as claimed in claim 26 is characterized in that: described data service comprises a plurality of data cells, and each data cell comprises path cost, and described path cost also comprises at least one guard byte; And

Wherein, for described definite protection swap data is inserted in the described data service, described particular network unit inserts described protection swap data in described at least one guard byte.

29. network as claimed in claim 28; it is characterized in that: each described data cell comprises Synchronous Transport Signal level 1 (STS-1), and described at least one guard byte is included in the Z3 that defines in the described path cost of each STS-1 and at least one in the Z4 byte.

30. network as claimed in claim 26 is characterized in that: each the described network element in described first group comprises that being configured to the described operating path of process transmits the switching fabric of described data service.

31. network as claimed in claim 26 is characterized in that: the described OC link of each bar in described first group comprises the reserved bandwidth through the described data service of described operating path.

32. network as claimed in claim 26 is characterized in that: the described OC link of each described second group bar comprises the reserved bandwidth through the described data service of described operating path.

33. network as claimed in claim 26 is characterized in that: at least one in the described first group described network element is in described second group.

34. network as claimed in claim 26 is characterized in that: described data service is by Synchronous Optical Network (SONET) standard definition.

35. network as claimed in claim 26 is characterized in that: described data service is by synchronous digital hierarchy (SDH) standard definition.

36. a preparation is coupling in the network element in the operating path of optical-fiber network, described network element comprises:

Routing table, it can be configured to have the input protection inlet that is used to assign the protection path wherein, and described protection path has a plurality of network element; Described protection inlet comprises the protection swap data;

Be used for monitoring the device of described operating path fault;

Be used for when described operating path detects fault, in described routing table, searching described protection inlet so that obtain the device of described protection swap data;

Be used for described definite protection swap data is inserted the device of data service; And

Be used for device that described data service is exported with the described definite protection swap data that is inserted into;

Wherein, the request that is suitable for being provided for disposing described protection path of described protection swap data reconfigures so that set up the instruction of each described network element in described protection path.

37. a preparation is assigned to the network element in the protection path of optical-fiber network, described network element comprises:

Be used to receive the device of data service;

Be used for monitoring the device of variation of protection swap data of the data service of described reception; And

Be used under described protection swap data changes situation, handling the device of described protection swap data; And

Wherein, the device that is used to handle described protection swap data comprises: be used for comprising the device that reconfigures described network element under the exchange instruction situation relevant with described network element at described protection swap data; And

Wherein, described protection swap data by with operating path that described protection path is associated in network element produce and be suitable for being sent to the network element in described protection path, at least one is not the Trail termination unit of described operating path in the described network element in described protection path.

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